The present invention relates to toothbrushes and, more particularly, to toothbrushes in which the head carrying the bristles is adjustable relatively to the handle to facilitate brushing and cleaning of the teeth, the spaces between the teeth and the gums.
The problems attendant upon the proper care and cleaning of the teeth are well known. The recommended actions for cleaning teeth are either brushing downwardly from the gums or, preferably, wriggling the brush with the ends of the bristles in contact with the teeth which is more effective method of removing food debris accumulated in the spaces between the teeth. Conventional toothbrushes are quite effective for brushing and cleaning the front surfaces of the teeth and gums and the front inter-tooth spaces by either of these recommended methods. However, difficulties arise when either method is applied to brushing the rear surfaces of the teeth and gums. Moreover, it is important that excessive brushing pressure is avoided when cleaning the teeth as, over an extended period, this is likely to wear the teeth and damage the gums.
Many different constructions of toothbrush have been proposed for facilitating thorough brushing and cleaning of all surfaces of the teeth and gums. One such construction described in U.S. Pat. No. 1,369,664 comprises a handle so arranged that a finger may be inserted into the handle to permit manipulation of the toothbrush, and a brush head which is articulated midway along its length and is connected to the handle by another hinged joint. All the joints are constructed so that there is sufficient friction to maintain the toothbrush, while in use, in the shape in which it is bent. U.S. Pat. No. 4,020,521 describes another arrangement in which the brush head is pivoted to the handle for rotation about an axis generally parallel to the bristles. Yet another construction is described in Austrian Pat. No. 279994 in which the toothbrush is formed in two parts articulated together approximately mid-way between opposite ends of the brush with adjustment about an axis perpendicular to the axis of the handle so that the brush proper can be cranked relative to the handle. The two parts are locked in a desired cranked position by an array of inter-engaging ribs and grooves and a locking screw.
In the prior constructions, the articulated connections are generally complicated, and in practice, do not provide for satisfactory brushing and cleaning of the rear surface of the teeth and gums, and/or do not provide for brushing and cleaning under a controlled pressure to alleviate wear of the teeth and damage to the gums. Hence, there is a need for a simple and inexpensive toothbrush having an adjustable head which will permit effective brushing and cleaning of all surfaces of the teeth and gums under a controlled pressure.